30bb

//version=5
indicator("BB Open SMA 30 (2.5 / 1.5)", overlay=true)

// 공통 설정
length = 30
src = open

// 중심선 계산 (표시는 안 함)
basis = ta.sma(src, length)

// 표준편차
dev = ta.stdev(src, length)

// BB 2.5
upper_25 = basis + dev * 2.5
lower_25 = basis - dev * 2.5

// BB 1.5
upper_15 = basis + dev * 1.5
lower_15 = basis - dev * 1.5

// 선 그리기
u25 = plot(upper_25, title="Upper 2.5", color=color.new(color.red, 0))
l25 = plot(lower_25, title="Lower 2.5", color=color.new(color.red, 0))

u15 = plot(upper_15, title="Upper 1.5", color=color.new(color.blue, 0))
l15 = plot(lower_15, title="Lower 1.5", color=color.new(color.blue, 0))

// 음영 처리
fill(u25, l25, color=color.new(color.red, 85))
fill(u15, l15, color=color.new(color.blue, 85))